What makes Mars the 'Red' Planet? Scientists have some new ideas

[Admin]

Mars is known as the "Red" Planet, but what actually makes it red? New research offers answers.

What makes Mars the 'Red' Planet? Scientists have some new ideas : Read more

 

[Unclear Engineer]

Because the ferrihydrite forms from exposure to cold water, I am wondering if its presence on Mars really indicates much water on the Martian surface, previously. There are apparently still annually forming ice caps on Mars. Could they temporarily form liquid water beneath the ice as they melt, allowing ferrihydrites to form, which then get blown around the planet when the ice is gone? If that sort of mechanism occurred over much of the planet's surface in the past, would it still have required lakes, rivers and oceans to produce what we see today?

I do realize that there are other indications of ancient liquid surface water on Mars. So my question is more about when Mars actually turned red. Was it mainly after the water was gone, or did it happen while the planet's surface was potentially suitable for life?

 

[danR]

So my question is more about when Mars actually turned red. Was it mainly after the water was gone, or did it happen while the planet's surface was potentially suitable for life?

What I have to question is that after all the Martian landers and rovers, none of them did any simple, almost trivial, tests for the (then-presumed) hematite. And yet, almost half a century ago, two (Viking) landers undertook rather sophisticated soil tests for life itself.

By the way, the lab simulations do not as yet falsify hematite; they are simply showing ferrihydrites to be a much more likely option.

 

[danR]

Can any of the current probes on Mars be configured to do a ferrihydrite test?
"Mars Curiosity Astrobiology Rover ChemCam Instrument Has Fired 1 Million Times" —Astrobiology, Sept. 2024

 

[Helio]

Because the ferrihydrite forms from exposure to cold water, I am wondering if its presence on Mars really indicates much water on the Martian surface, previously. There are apparently still annually forming ice caps on Mars. Could they temporarily form liquid water beneath the ice as they melt, allowing ferrihydrites to form, which then get blown around the planet when the ice is gone? If that sort of mechanism occurred over much of the planet's surface in the past, would it still have required lakes, rivers and oceans to produce what we see today?

Good question, though I would assume that liquid water would need to be deeper below the surface due to the lack of air pressure.

From Wiki (Ferrihydrite), it's noted that this can come from hot springs and other regions, including cold water. So perhaps this article was implying that the given cold-only water was appropriate, ignoring less likely scenarios.

 

[Helio]

What I have to question is that after all the Martian landers and rovers, none of them did any simple, almost trivial, tests for the (then-presumed) hematite. And yet, almost half a century ago, two (Viking) landers undertook rather sophisticated soil tests for life itself.

By the way, the lab simulations do not as yet falsify hematite; they are simply showing ferrihydrites to be a much more likely option.

Yeah. Hematite does seem more likely since the chemical formula Fe2O3 is simpler than for ferrihydrite. It would seem likely that this would have been studied, and maybe it's in their formal paper.

 

[Helio]

What impresses me is that they took the color of Mars and turned it into more solid -- I want to say "iron-clad" for some reason -- evidence for liquid water.

By coincidence this week, while reading"Decoding The Stores: A Biography of Angelo Secchi, Jesuit and Scientist", (Chinnici), I came across a section on the 40 exquisite color drawings of Mars by Secchi. He noted that the ice caps appeared "light yellow", but of course, they will look white in most cases.

But, in his case, Mars was low in the sky (AM2.1), which could have made a white ice cap appear more yellow than otherwise. Perhaps Rome in the late 1800s had higher than normal particle counts. Maybe oil-burning lighting at that time caused fairly high particle counts in the air, causing slight reddening of celestial light.

His best and favorite scope was a Merz 8" refractor. He placed the Sun with Capella (a yellowish star) in his three (later 5) spectral star types. [Color was just a general label; their spectra determined the star Type, with Type II being the "yellow stars". Type I were "white". Type II were "red"] Perhaps it had some chromatic issues, as well, contributing to his color account.

[Another active astronomer at the time, Donati, and friend of his, also worked with the idea that star color and temperatures were related. Harvard researches came to a similar conclusion a little later.]

It's just interesting how color topics can present some fun astronomy lessons.

 

[johnpucci]

Rust on the earth requires oxygen. Does this mean that Mars had O2 sometime in the past? If so where did it come from?